Internal combustion engine cylinder



Oct. 15, 1957 A. c. CAVII EER INTERNAL COMBUSTION ENGINE CYLINDER Filed May 12. 1955 INVENTOR ALBERT QCAVILEER BY 5 xzw gwz/ ATTORNEY 2,809,873 INTERNAL COMBUSTION ENGLNE CYLINDER Albert C. Cavileer, Glen Burnie, Md. Application May 12, 1955, Serial No. 508,005

Claims. (Cl. 309-2) (Granted under Title 35, U. S. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to a liner for an internal combustion engine and more particularly to a novel structure wherein characteristics are obtained which are desirable from a wear standpoint and at the same time maintaining the lubricating oil'consumption at a low value.

It is customary in internal combustion engine practice, especially for units of large capacity, to chromium plate the inner surface of the cylinder or cylinder liners to thereby increase the life expectancy thereof. All

chromium is porous to some extent and considerable effort and energy has been expended in obtaining optimum porosity for maximum wear life of the cylinder. It has been found, however, that within certain limits, applying a coating of chromium that has a high degree of porosity on a wearing surface generally produces a long wearing cylinder but is has also been established that when the cylinders are thus plated with high porosity the lubricating oil consumption is much higher than when the coating is of a low porosity. The usual method of chromium plating is therefor that which might be expected, namely to arrive at a compromise degree of porosity which is not completely satisfactory from either the wear or lubricating oil consumption viewpoint. The present invention combines the desirable properties of the two types of chromium plating as will later be more fully explained.

An object of the present invention is to improve on the present cylinder ofinternal combustion engines.

Another object is to provide a novel chromium plating arrangement for internal combustion engine cylinder wearing surfaces.

A further object of the invention is the provision of an internal combustion engine cylinder wherein a predetermined area is plated with a chromium of a given porosity and another selected area is plated with the chromium of a different porosity, the porosity being selected for optimum results.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings in which like reference numerals designate like parts through the figure and where- The single figure shows a longitudinal elevation in section of a cylinder liner showing a preferred embodiment of the invention.

Referring now to the drawing there is shown in the figure a cylinder liner which might be utilized in a modern diesel engine and in which reference character it) indicates the liner body generally. A plurality of ports 11 are arranged substantially as shown to admit scavenging air from the air box to the cylinder. The

2,809,873 Patented Oct. 15, 1957 disclosed liner is a two piece water jacket type, made of steel. A water jacket 14 fits in embracing relation over the liner forming a chamber therebetween to receive cooling water. Reference character 12 designates the cooling water inlet and 15 illustrates a type of baflle plate utilized for the proper distribution of water. The water flows through the inlet 12 past baflleplate 15 and through ferrules 13 into the cylinder head (not shown). These ferrules are made water tight by synthetic rubber sealing rings. A further seal ring 16 seals the lower portion of the junction between the water jacket and the liner body. Slidably received within the liner is a piston 17 which has compression ring grooves 18 at the upper portion thereof, which are illustrated merely for the purpose of showing the structure; and a single ring, reference character 19, is shown in situ to illustrate how it engages the internal surface of the liner at its usual well-known manner. At the lower portion of the piston are formedv oil ring grooves 2% having a series of holes 21 bored through the thickness of the piston to admit and pass lubricating oil picked up by the wiping action of the ring and to pass it through the piston skirt back to the crank case. An oil ring 22 is shown engaging at the peripheral extremities thereof the inner surface of the cylinder liner.

It is known that chromium plating of the wearing surface ofa cylinder will increase the life and reliability of an engine. It is also known that plating of chromium of a high degree of porosity will usually produce a longer wearing cylinder because of the ability of the pores, and sometimes channels, to entrap and hold oil to thereby better lubricate the piston rings as they wipe over the same; however, when this oil is not properly wiped clean the flame of combustion being exposed thereto will burn, the same resulting in a very high lubricating oil consumption rate. As a result the degree of porosity used is a compromise between long life and reasonable oil consumption. In the illustrated invention, in contradistinction to the above, the upper end or the end of the cylinder liner over which ride the compression rings, which is the area where the greatest wear occurs, is plated with chromium of a relatively high porosity. The percentage of porosity indicates the percent of voids appearing in the surface. The upper area is also subject to scoring and scratching by the piston. The lower end or the end of a cylinder liner over which slide the oil control rings, is usually less affected by wear, scoring, or scratching and it is the area where the oil must be controlled. In this invention, this area is plated with a chromium of a relatively low porosity. T his produces a cylinder in which lubricating oil consumption is controlled without resorting to severe oil rings which tend to induce extremely high lateral pressure on the cylinder and increase the friction thereby. In the drawing the portion of the cylinder from the top thereof down to the line A is plated with chromium plating of about 30% porosity illustrated in the enlarged view 23. The area from the bottom of the cylinder up to about the line A, or somewhat lower, is plated with a chromium of from 8 to 10% porosity as illustrated in the enlarged portion thereof 24. The line B indicates approximately the lower limit of the travel of the top of the piston.

It will be seen therefore that the areas wiped by the compression rings have the porosity most suitable to the service intended and those peripheral areas wiped by the oil ring are also provided with a type of porosity which will provide optimum oil consumption for the service expected.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. In an internal combustion engine having slidable pistons, a cylinder having an inner wearing surface in relative sliding engagement with a plurality of piston carried rings, including a compression ring and an oil control ring, a relatively thin coating of porous chromium covering the wearing surface, the chromium porosity being axially variable with relatively greater porosity in the area adapted to be engaged by said compression ring, said area having the higher temperatures and higher pressures in the cylinder, and with relatively lesser porosity in the area adapted to be engaged by said oil control ring.

2; In an internal combustion engine the combination comprising a cylinder having a chromium internal wearing surface of variable porosity, a piston slidable in said cylinder, a plurality of axially spaced rings carried by said piston and slidable against discrete areas of said wearing surface, the area of said wearing surface in the fuel combustion region of said cylinder having a maximum porosity.

3. A liner adapted to be fitted into a cylinder of an internal combustion engine having a reciprocating piston provided with a compression ring and an oil control ring, said liner having a chromium internal wearing surface of axially variable porosity, a first peripheral area of said surface adapted to be engaged by said compression ring having a porosity of about 30 percent, and a second peripheral area of said surface adapted to be engaged by said oil control ring having a porosity of about 8-10 percent.

4. A cylinder liner for an internal combustion engine having a piston slidable in said liner, the piston having axially spaced compression rings and one or more oil control rings, said liner having a porous chromium internal Wearing surface, the peripheral area of said surface adapted to be engaged by said compression rings having a porosity greater than the porosity of the area of said surface adapted to be engaged by said oil control rings.

5. In an internal combustion engine the combination comprising a cylinder having a chromium internal wearing surface of variable porosity, a piston slidable in said cylinder, said piston having axially spaced compression and oil control rings, a first cylindrical area of said cylinder extending to span the travel of said compression ring thereby being normally subjected to relatively high temperatures, pressures and degrees of wear, a second cylindrical area of said cylinder extending to span the travel of said oil control ring thereby being normally subjected to relatively low temperatures, pressures and degrees of Wear, the entire first cylindrical area of said cylinder having a relatively high and substantially uniform degree of porosity, and the entire second cylindrical area of said cylinder having a relatively "low and substantially uniform degree of porosity.

References Cited in the file of this patent UNITED STATES PATENTS 2,227,307 Hildabolt Dec. 31, 1940 2,433,457 Jarrett et al. Dec, 30, 1947 

